There are various text distribution apparatus for distributing text among printers. For instance, reference may be had to U.S. Pat. No. 4,754,428 to T. G. Schultz et al. issued June 28, 1988, which describes a distribution apparatus and method for distributing documents to remote sites. This reference allows for the display and printing of the document by devices whose format is different than that of the originating location. The system convert printer signals to data to be transferred to remote location to then to be converted back to printer signals to be used in printing a copy of the original document. However, this reference does not provide any method of generating hard copy output of a selected screen image at any attached printer without host application intervention.
U.S. Pat. No. 4,713,780 to T. G. Schultz et al. issued Dec. 15, 1987 describes a distribution method for distributing and displaying documents at a remote site. This reference allows for the display of the document by devices whose format is different than that of the originating location. The reference converts text data from a document source to a character and position format to be used in redisplaying the document at a remote site. This patent does not generate hard copy output of a selected screen image at any attached printer without host application intervention.
U.S. Pat. No. 4,641,263 to E. H. Perlman et al. issued Feb. 3, 1987 describes a method and apparatus for printing to a remotely attached parallel printer via a parallel port. It provides for parallel to serial data conversion, transmission of the converted data, and conversion from serial to parallel data to be printed at a remotely attached parallel printer. However, this patent does not generate hard copy output of a selected screen image at any attached printer without host application intervention.
U.S. Pat. No. 4,651,278 to A. Herzog et al. issued Mar. 16, 1987 describes a host application to All Points Addressable (APA) printer interface. This patent provides a process for interconnecting an All Points Addressable printer to a host application program, but also does not provide for generating hard copy output of a selected screen image at any attached printer without host application intervention.
U.S. Pat. No. 4,556,959 to W. H. Allen et al. issued Dec. 3, 1985 describes a method of determining and selecting printer options for work stations and printers attached via a Local Area Network (LAN). The patent provides a method for sensing and selecting printer options from a Local Area Network (LAN) attached work station, but also does not provide a method of generating hard copy output of a selected screen image at any attached printer without host application intervention.
U.S. Pat. No. 4,835,673 to R. J. Rushby et al. issued May 30, 1989 describes a method of dynamic allocation of hardware resources on a Local Area Network (LAN) based distributed network. This patent provides a method of sharing resources among processors attached via a Local Area Network (LAN). This patent does not provide any method of generating hard copy output of a selected screen image at any attached printer without host application intervention.
Within IBM, as disclosed by IBM TDB Vol. 32, No. 9A, 2/90, pp 111-12 entitled PRINTER PASS THROUGH PROTOCOL, it has been proposed to allow a program running on an IBM System/36 to use a printer on a Local Area Network (LAN) attached Personal Computer. However, this technical bulletin does not provide a method of generating hard copy output of a selected screen image at any attached printer without host application intervention. Other IBM publications include IBM TDB Vol. 31, No. 10, 3/89, pp 179-81 entitled USER INTERFACE TO A PRINT FACILITY which describes an interface to be used in the presentation of print facilities to a host application; and also IBM TDB Vol. 31, No. 7, 12/88, pp 260-61 entitled PRINT BUFFERING ALGORITHM describes a method by which printer data can be buffered and CPU time required to process the print job minimized based on printer characteristics, do not show any method of generating hard copy output of a selected screen image at any attached printer without host application intervention.
Similarly, IBM TDB Vol. 20, No. 6, 11/77, pp 2275-77 entitled PRINT AUTHORIZATION MATRIX describes a system by which a display system controller (Control Unit) can be configured so that attached displays can access a particular subset of attached printers. This display/printer association can only be made between devices that are both attached to the same Control Unit. This reference does not provide for generating hard copy output of a selected screen image. This operation can take place only between devices that are both attached to the same Control Unit.
IBM U.S. Pat. No. 3,573,741, issued to Bruce D. Gavril Apr. 6, 1971 illustrates a versatile general purpose control unit. It has means for interconnecting two peripheral devices though the control unit without computer activity during data transfer, and eliminates unnecessary interference within the system memory or with the I/O channel. This reference does not provide the local copy of screen function for generating hard copy output of a selected screen image chosen by the operator.
In foreign publications, there are similar deficiencies. Great Britain Patent GB2185607-A, 7/22/87 describes an apparatus used to connect a terminal to a processor which can be used to offload the processor by performing local computing functions. This U.K. patent does not show any way to generate hard copy output of a selected screen image at any attached printer without host application intervention. European Patent EP-395890-A, 11/7/90 describes a local print controller which offloads a central print controller.
From a review of these many references it will be seen that there is still a need for a method by which hard copy output of a selected screen image can be generated, regardless of the attachment of the display and printer. Furthermore we have seen that there should be provided as part of the system a way of generating hard copy output of a selected screen image at any attached printer without host application intervention.
We recognized that the IBM 3274 and 3174 Control Units can be connected for data transfer from an IBM 3270 display system to an IBM 328X printer. In this regard reference may be had to the IBM 3270 Information Display System: 3274 Control Unit Description and Programmer's Guide (IBM publication number GA23-0061).